convert enums to strongly typed c++11 enums
Like the title says, and make the SISO enums the correct size also to eliminate #3.
changed pdu::Transmitter::CryptoKeyId::EncryptionMode to a strongly typed enum. refs #5
converted geospatial::MapProjection/EarthEllipsoid/Hemisphere to strongly typed enums. refs #5
converted utility::Clock::TimestampMode to a strongly typed enum. refs #5